This still sounds like it has its roots in political philosophy to me. Like Stalinism or Nazism (as you say), but, in the case of Rapture's removal from dominant society, the cultists have become the dominant society/state. In Rapture surely the two would be interconnected?
Marx socialism, Smiths economical liberalism and Mills social liberalism was coherent systems that had things thought through in almost all aspects. They are deeply rational and one could almost say "scientific".
What Marx, Smith and Mill have in common is their great emphasis on rationality, with rationality comes science, the emphasis on what can be seen, optimization of the known system etc, but they usually leave out the emotional realm, the existential questions. Each of them came into being before Freud.
If you analyze at Stalinist soviet, Mao's china and the nazi movement from a rational perspective you might discover that they lack a coherent system behind them as if they are made up on the go. There's little in form of structure and consistency in them, instead they seemingly sway back and forth, exploiting the situation through symbolism and powerful emotions through suggestive language and rhetoric.
What these powerful movements had to offer was a meaning for the individual, at least for the few lucky the ideology have chosen. All they ask in return is submission to it's abstract cause. Religions are also masters of this realm, so are sects, cults and anyone who learned how to manipulate peoples inner powerful drives to do their bidding.
The closest you come to analyze these drives from a scientific standpoint is psychology. The old rational political philosophies didn't understand them, even if Hobbes spoke about fear and Marx about alienation. We still don't know how they work, but anyone with some experience with psychology know that humans aren't rational beings (which Smith, Mill and Marx presumed).
The way they are connected is that rational political philosophies often reject the value of these emotions, where as the more emotional political movements often reject the rational political philosophies. Rationality will reject religion, religion will reject rationality. And if you are a rational person, but know how to exploit peoples emotions, you can start a cult and get the mass to do your bidding, without ever presenting a coherent system.